# Surface areas and volumes of spheres

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"Surface areas and volumes of spheres"

```					Surface areas and volumes of
spheres
A sphere is a set of points in space that are a fixed
distance from a given point called the center of the
sphere.
A radius of a sphere is a segment whose endpoints are
the center of the sphere and any point on the sphere.
Surface area of a sphere
• The surface area of a sphere is given by
the following formula, where r is the
• S = 4  r2
Calculating surface area
• Find the surface area of a sphere with a
• S = 4  (8)2
Volume of a sphere
• The volume of a sphere is given by the
following formula, where r is the radius of
the sphere
• V = 4/3 r3
Calculate volume of a sphere
• Find the volume of a sphere with radius
16 m.
• V = 4/3  (16)3
Hemisphere
• A hemisphere is half of a sphere.
• A great circle is a circle on a sphere
that divides the sphere into 2
hemispheres.
• An example of a hemisphere is the
equator since it divides the Earth into
2 congruent hemispheres
Volume of a hemisphere
• Volume of a hemisphere is equal to half
the volume of the sphere with the same
radius V = 1/2 (4/3  r3)
• Surface area of a hemisphere is the half the
surface area of the sphere plus the area of
the great circle
• SA = 1/2 (4  r2) + r2
Calculating Surface area and
volume of a hemisphere
• Find the surface area and volume of a
hemisphere with an 18-foot diameter.
Practice
• 1. Find the surface area of a sphere with an 8-
meter diameter to the nearest hundredth of a
square meter.
• 2. Find the volume of a sphere with a diameter
of 22 in., to the nearest hundredth of a cubic
inch.
• 3.Find the surface area and volume of a
hemisphere with a 16-foot radius to the nearest
hundredth of a foot.
• 4. A snowglobe's circumference is 20 cm. How
much water does it take to fill the globe, to the
nearest hundredth of a cubic cm.

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 views: 55 posted: 10/5/2012 language: English pages: 9